What is Strabismus?
Strabismus is when one eye points straight ahead; the other eye, elsewhere. The misaligned eye may point in towards the nose (esotropia) or out towards the ear (exotropia). In other cases it may point up or down. Whichever direction of misalignment, the main concern is that it’s aimed in the wrong direction. Most of the time, strabismus develops in young, otherwise healthy children.
How does Strabismus Develop?
6 muscles surround the eye and control where it aims. Normally all these muscles match with the 6 of the other eye, but in strabismus they do not. A common misconception about strabismus is that it develops from a weak muscle but that is almost never the case. In fact, the 6 muscles outside of each eye are much stronger than necessary, sometimes dozens times stronger than they need to be. The deviation between the two eyes is primarily caused by a miscommunication between the brain and the eyes.
Why is Strabismus a problem?
Two major issues arise from strabismus. The first concern is purely cosmetic. Infants and toddlers are unaffected by this but school aged children, teens and adults are more conscious of the appearance. The other problem from strabismus is a functional one. People with normal vision match the input from both eyes to create one image of the world. In strabismus, if one eye deviates from the other, double images result. Because double vision is unbearable, the child will shut off or “suppress” the information from the misaligned eye. If this suppression occurs for too long, one of the eyes can become impaired and develop amblyopia; much like a broken arm which remains in a cast for too long becomes severely weakened.
No Treatment: What happens if nothing is done to counteract these problems? Without treatment the problem will remain the same, or even become more deeply ingrained; it is almost never reversed naturally.
Surgery: The aim in surgery is to straighten the eyes, yet the procedure does not guarantee they remain straight. Even if the eyes are cosmetically straight, this does not ensure that the patient knows how to use them as a team. If the person doesn’t learn how to use the eyes together, a misalignment will often return years or even months after surgery. Second, third and other subsequent surgeries may be recommended.
Vision Therapy: It is important to remember that because strabismus is not due to a weak muscle, vision therapy is not designed to make the muscles stronger. Vision therapy is a set of procedures designed to help the patient learn to straighten the eyes and keep them that way. This helps the patient’s eye-hand coordination, depth perception and reading often becomes faster. The clumsiness usually experienced when the eyes are not aligned also reduces.